SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '299f75391d75c4786e66f0b3e270c54985f322b11be132d012c8be817552e9a6' 
  AND token = 'epJUdfzdjdq8PEuUKf5wUZlnYFusC74XJIi1iIn2Xgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}